Automatic fluid-pressure train-brake



(No Model.)

W. H. CLARKE, AUTOMATIC FLUID PRESSURE TRAIN BRAKE.

No. 552,234. Patented Dec. 31, 1895.

ANDREW EGRAHAM.PMOYOLITNQWASHINGTON DC NITED STATES IVILLIAM II. CLARKE,OF BROOKLYN, NEXV YORK.

AUTOMATIC FLUID-PRESSURE TRAIN-BRAKE.

SPECIFICATION forming part of Letters Patent No. 552,234, dated December31, 1895.

Serial No. 544,228. (No model.)

To ctZZ whom it may concern.-

Be it known that I, WILLIAM H. CLARKE, a citizen of the United States,residing at Brooklyn, in the county of Kings and State of New York, haveinvented certain new and useful Improvements in Automatic Fluid-Pressure Train-Brakes, of which the following is a full, clear, andexact description.

This invention relates to automatic fluidpressure train-brakes.

In automatic air-brake systems such as the Westinghouse it is thepractice in making an emergency application of brakes to vent both theauxiliary reservoir and the train-pipe into the brake-cylinder, in orderthat an extra pressure may be obtained. This venting of the train-pipeinto the cylinders not only hastens the stop, by furnishing extrapressure, but incidentally hastens the response of the triple valvesthroughout the train. This second advantage is naturally more pronouncedwhen the train-pipe is vented into the atmosphere instead of into thebrake-cylinder; but in so doing it becomes necessary and desirable todevise other means for securing the maximum braking stress upon thebrake-shoes, and compensating for the loss of air from the train-pipe.

By my invention I utilize the standard (lVestinghouse) capacity relationbetween the auxiliary reservoir and the brake-cylinder, and limit thepressure which shall enter the brake-cylinder in either service oremergency application of brakes to a predeten.

mined amount in each, regardless of the pressure in the train-pipe orthe action of the ordinary triple valve; and then by changing theleverage of the brake-rigging I am able to secure a maximum brakingstress in emergencies without venting extra pressure into thebrake-cylinder from any source or sources other than the auxiliaryreservoir. Hence the air vented into the brake-cylinder from thetrain-pipe under the present practice may be vented into the atmosphere,not only with out loss of brake-pressure, but with the gain of quickeraction.

My invention may be carried out by merely supplying an automatic valveadapted to limit the pressure which shall enter the brake-cylinder in aservice application of brakes to a predetermined small amount of, say,forty pounds, and which will also limit the pressure which shall enterthe brake-cylinder in an emergency application of brakes to apredetermined large amount of, say, fifty pounds, and by an adjustmentof the leverage of the brake-rigging, so that these pressures willcreate the same braking stress upon the brake-shoes as is now created bythe aid of higher air-pressures.

My invention is illustrated in the accompanying drawing, in which thefigure is a side elevation of a standard brake-cylinder, auxiliaryreservoir, and triple valve, such as are used ordinarily onfreight-cars, parts being broken away to illustrate the devicesconstituting my invention.

Referring to the drawing by letter, A represents an ordinarybrake-cylinder, B an ordinary auxiliary reservoir, and C a triple valve.12 is the port ordinarily provided for admitting air from the auxiliaryreservoir to the interior of the triple valve, and c is the portadmitting air from the triple valve into the brake-cylinder, by way of apipe 0, which extends from one end of the reservoir to the other,connecting the triple valve and cylinder together. In the usualunderstood operation of these parts the triple valve controlscommunication between the auxiliary reservoir and the brake-cylinder,and between the train-pipe and both the brake-cylinder and auxiliaryreservoir. In adapting my invention to this form of apparatus, I providea small cylinder 6, opening at one end through .a restricted passage 6into the pipe or passage 0, leading from the triple valve to thebrakecylinder. In the cylinder e is a piston e having a stem 6 which bymeans of lugs e embraces a slide-valve f, arranged to cover and uncoverthe port 1), leading from the auxiliary reservoir to the triple valve.The piston is acted upon by the spring 6 with a tendency to hold thepiston at the inner end of its stroke, in which position the portb isuncovered. This spring will be of such power as to resist any pressurebeneath the piston coming from the brake-cylinder passage, less than thepressure adopted for service application of brakes, but to yield topermit the piston to move outward and thus close port I) as soon as thepressure beneath the piston reaches the service amount.

The operation of the apparatus is as follows: In a service applicationof brakes the pressure in the auxiliary reservoir is admitted slowlyinto the brake-cylinder, and the pressure rises at about the same speedbeneath piston e as it does in the brake-cylinder, and as soon as thepressure reaches the maxim um for a service stop the piston e is forcedoutward and the port Z) is closed, thus preventing anyfur ther admissionof air into the brake-cylinder from the auxiliary reservoir. Inemergency applications of brakes the action ofthe triple valve is toopen a comparatively large and free passage for the air intothebrake-cylinder, and the pressure therein instead of rising slowlybuilds up very suddenly and because of the restricted passage betweenpipe 0 and cylinder e piston e will not feel the rise, of pressure asrapidly as it enters the brakecylinder. The result will be that anaccumulation of pressure in the brake-cylinder will take place,amounting to a number of pounds above that at which the spring e is set,the excess depending upon the size of passage 6. \V hen the pressure incylinder e overcomes the spring, port Z2 will be closed. It will thus beseen that by gaging the power of the spring a and the size of thepassage e the working pressures used in both service and emergencyapplications of brakes are predetermined.

My intention is to use in connection with this invention a triple valvewhich 011 an emergency reduction of pressure at theengineers valve willopen the train-pipe to the atmosphere and not to thebrake-cylinder, asin the present practice. Atmosphericexhaust will give a very quickaction throughout the train and possesses other advantages unnecessaryto mention here. \Vith brake-rigging adjusted to give the maximum stressupon full expansion of the auxiliary reservoirI do not need thetrain-pipe pressure in the cylinders and therefore can afford to vent itto the atmosphere. I am aware that an increase in the leverage of thebrake-riggin g means an increased length of stroke for the brake-cyLinder piston, but this increase will be slight and of littleconsequence.

Although my intention is to use an atmosphere-exhaust in connection withmy invention, it is obvious that if a standard \Vestinghouse triplevalve,venting both the train-pipe and auxiliary reservoir into thecylinder upon emergencies, is used, the action will be the same, for thepiston e will be moved under the same conditions as before, and theauxiliary pressure will be shut off before the pressure in thebrake-cylinder rises above the normal. It is well understood that if apressure above the normal should enter the'brake-cylinders with myincreased leverage the wheels would become locked and slide. This,however, cannot happen, and my system is therefore interchangeable withthe standards now in use.

I have shown and described my valve as located inside of the auxiliaryreservoir, but this is desirable only when the cylinder, reservoir, andtriple valve are combined as illustrated. It is obvious that myinvention is not limited to any particular location, nor to theapplication to freight-cars alone. It conte1nplates a piston-acted uponby brake-cylinder pressure through a restricted passage to con trol theport leading from the auxiliary res ervoir to the triple valve.

Having thus described my invention, I claim 1, In an air brake system,the combination of a brake cylinder, an auxiliary reservoir, and atriple valve with a port between the reservoir and triple valve, and avalve controlling said port the valve being moved to close the port,under the pressure in the brake cylinder.

2. In an air brake system, the combination of a brake cylinder,auxiliary reservoir and a piston subjected to the pressure in the brakecylinder, said piston moving under such pressure to control a portleading from the auxiliary reservoir to the triple valve,substantiallyas described.

3. In an air brake system, the combination of a brake cylinder,auxiliary reservoir and a piston subjected to the pressure in the brakecylinder, said piston moving under such pressure to control a portleading from the auxiliary' reservoir to the triple valve, and a springacting upon the piston in opposition to such pressure.

4. In an air brake system, the combination of a brake cylinder,auxiliary reservoir, and a piston subjected on one side to the pressurein the brake cylinder,through a restricted passage, and on the otherside to a fixed counter pressure, said piston controlling a port leadingfrom the auxiliary reservoir to the triple valve, substantially asdescribed.

5. In an air brake system, the combination of a brake cylinder,auxiliary reservoir, triple valve and a piston subjected to the pressurein the brake cylinder through a restricted passage, said pistoncontrolling a port leading from the auxiliary reservoir through thetriple valve to the brake cylinder, substantially as described.

6. In an air brake system, the combination with a brake cylinder,auxiliary reservoir and triple valve, the brake cylinder and triplevalve being connected by a pipe leading through the auxiliary reservoir,and the auxiliary reservoir and triple valve by a port, of a cylinderand piston located inside of the auxiliary reservoir, the cylindercommunicate ing with the said pipe througlla restricted pasconstantlysubjected to the pressure in the IQ sage and a valve moved by saidpiston and brake cylinder, substantially as described. controlling theport between the auxiliary res- In testimony whereof I subscribe mysignaervoir and triple valve, substantially as deture in presence of twowitnesses.

scribed.

7 In an air brake system, the combination WILLIAM H. CLARKE. of a brakecylinder, auxiliary reservoir and Witnesses: triple valve, with a valvecontrolling a port WM. A. ROSENBAUM,

between the reservoir and triple valve and FRANK S. OBER.

